Mobile network operators utilize Alternative Access Vendors (AAVs) where the operator's network does not extend to a mobile cellular location. The AAV provides a wide area networking network interface (e.g., a user network interface, or “UNI”) and provides a virtual circuit between the mobile cellular location and the carrier's core network. The networking interface may be Carrier Ethernet, Multi-protocol Label Switching (MPLS), Frame Relay, Asynchronous Transfer Mode (ATM), or other interface type that supports virtual circuits or virtual channels (VC).
A VC is provisioned with a committed data rate (CDR), also called a committed information rate (CIR), which is specified in a service level agreement (SLA). In the SLA, the AAV typically promises to deliver at least a certain percentage of packets or frames transmitted below the CIR, usually 99% or 99.9% of frames. The amount of CIR specified in the SLA is often tied to the cost of the AAV's service, with a higher CIR costing more money. A peak information rate (PIR) is the maximum burst speed allowed on the VC, with packets that exceed the CIR being a “best effort” and therefore non-guaranteed. The carrier and the AAV typically employ policers at the UNI handoff to monitor and shape throughput to conform to the CIR and/or PIR.